Efficacy of Intermittent or Continuous Very Low-Energy Diets in Overweight and Obese Individuals with Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analyses

Abstract

Objective. This study is aimed at investigating the efficacy of a very low-energy diet (VLED) in overweight and obese individuals with type 2 diabetes mellitus (T2DM). Methods. We thoroughly searched eight electronic resource databases of controlled studies concerning the efficacy and acceptability of intermittent or continuous VLEDs in patients with T2DM compared with other energy restriction interventions. Results. Eighteen studies (11 randomized and seven nonrandomized controlled trials) with 911 participants were included. The meta-analyses showed that compared with a low-energy diet (LED) and mild energy restriction (MER), VLED is superior in the reduction of body weight (mean difference (MD) MDLED=−2.77, 95% confidence interval (CI) CILED=−4.81 to−0.72, PLED=0.008; MDMER=−6.72, 95%CIMER=−10.05 to−3.39, PMER<0.0001), blood glucose (MDLED=−1.18, 95%CILED=−2.05 to−0.30, PLED=0.008; MDMER=−6.72, 95%CIMER=−10.05 to−3.39, PMER<0.0001), and triglyceride (TG) (MDLED=−0.35, 95%CILED=−0.58 to−0.12, PLED=0.002; MDMER=−0.55, 95%CIMER=−0.93 to−0.17, PMER=0.005) levels at the end of the intervention. After the follow-up (1–5 years), no obvious difference in weight loss (MD=−0.84, 95%CI=−3.01 to 1.32, P=0.45, I2=0%) and TG level (MD=−0.25, 95%CI=−0.55 to 0.06, P=0.12, I2=0%) between VLEDs and LEDs was evident, but VLED is more effective in glycemic control (MD=−1.43, 95%CI=−2.65 to−0.20, P=0.02). Compared to bariatric surgery, VLEDs offered comparable effects on weight loss (MD=2.51, 95%CI=−9.52 to 14.54, P=0.37), glycemic control (MD=0.37, 95%CI=−0.22 to 0.96, P=0.22), TG (MD=−0.3, 95%CI=−0.74 to 0.17, P=0.7), and insulin resistance improvement (MD=−1, 95%CI=−2.7 to 0.7, P=0.25). Conclusion. Dietary intervention through VLEDs is an effective therapy for rapid weight loss, glycemic control, and improved lipid metabolism in overweight and obese individuals with T2DM. Thus, VLEDs should be encouraged in overweight and obese individuals with T2DM who urgently need weight loss and are unsuitable or unwilling to undergo surgery. As all outcome indicators have low or extremely low quality after GRADE evaluation, further clinical trials that focus on the remission effect of VLEDs on T2DM are needed.

Dietary Interventions to Treat Type 2 Diabetes in Adults with a Goal of Remission: An Expert Consensus Statement from the American College of Lifestyle Medicine

“…[52][53][54][55][56] Dietary Specifics and Types of Diets Remission of T2D requires a sufficient reduction in absorbed calories to decrease adiposity and insulin resistance. 8,[57][58][59] Studies consistently demonstrate that using liquid meal replacements can significantly reduce energy intake and cause weight loss. [59][60][61] For many individuals, however, foodbased approaches are better accepted than liquid meal replacements.…”

Role of lifestyle and glucagon‐like peptide‐1 receptor agonists for weight loss in obesity, type 2 diabetes and steatotic liver diseases

“…51,52 The key to success of lifestyle interventions resides in caloric reduction, as hypocaloric diets were shown to be most effective in terms of weight loss, glycemic control, and effects on liver-related outcomes. [53][54][55] Specific diets, mainly based on modification of macronutrient intake, such as low-carbohydrate, [56][57][58][59][60] very-low-carbohydrate, 57,58,[61][62][63] ketogenic, 62,[64][65][66][67] low-fat, 61,63 low glycemic, high-protein, [68][69][70] meal replacement 71 and vegan diets 61 have proven beneficial effects, but mostly when combined with concomitant energy restriction 72 (Figures 3 and 4; Tables S1 and S2). Mediterranean diets seem to be most effective in improving MASLD, even in the absence of weight loss 73-75 (Table S3).…”

Current Perspectives on the Role of Very-Low-Energy Diets in the Treatment of Obesity and Type 2 Diabetes in Youth

“… 46 Similarly, a 2020 systematic review of 18 studies reported that, compared to bariatric surgery, VLEDs offered comparable effects on weight loss, glycemic control, triglycerides, and insulin resistance and suggested that a VLED approach be used for individuals unsuitable or unwilling to undergo surgery. 47 …”

“…46 Similarly, a 2020 systematic review of 18 studies reported that, compared to bariatric surgery, VLEDs offered comparable effects on weight loss, glycemic control, triglycerides, and insulin resistance and suggested that a VLED approach be used for individuals unsuitable or unwilling to undergo surgery. 47 The findings from the DiReCT study led to the rollout of a VLED program in primary care in the UK, in what was termed a "diabetes remission service". 48 Despite the growing acceptance of the role of a VLED program for weight loss and type 2 diabetes treatment in adults, there remains significant hesitation in their use in youth (see sections, VLEDs in Clinical Practice and Safety of VLEDs in Youth).…”